JPH029204Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention consists of a mixture jet for injecting a mixture formed by mixing pulverized fuel and air or other gas into a boiler or various industrial furnaces, and an outside of the mixture jet. The present invention relates to an improvement in a burner for pulverized fuel, which comprises an annular jet orifice into which air or a mixture of air and other gas is injected from the surrounding area.

Examples of conventional burners for pulverized fuel of this type are shown in FIGS. 1 and 2.

In this embodiment, combustion air 012 sent from a ventilation device (not shown) is separated into primary air 013, secondary air 014, and tertiary air 015 within the burner.

The primary air 013 becomes a swirling flow by the primary air swirling blades 09 provided in the primary air passage 01,
The primary air is injected from the primary air outlet 05 into the furnace interior 021.

The secondary air 014 forms a swirling flow by the secondary air swirling vane 010 provided at the inlet of the secondary air passage 03, passes through the secondary air passage 03, and is discharged from the secondary air outlet 07 into the furnace 021. It is now being sprayed to

The tertiary air 015 forms a swirling flow by the tertiary air swirling vane 011 provided at the entrance of the tertiary air passage 04, passes through the tertiary air passage 04, and exits from the tertiary air outlet 08 into the furnace 021. It is now being sprayed to

On the other hand, pulverized fuel is produced by using air or other gas as a conveying fluid from pulverization equipment (not shown) to create a mixture with 0
18, the pulverized fuel is fed into the mixture passage 02 in the burner through the pulverized fuel supply pipe 016, and is injected into the furnace 021 from the mixture jet port 06 for combustion.

The auxiliary combustion burner 017 is used to ensure the ignition of the mixture 018 flame when it is difficult to burn the mixture 018 alone, but liquid fuel or gas fuel 019, which is easy to burn, is used as the fuel. It is becoming more and more common. Note that 020 is a burner throat.

Further, as other examples of conventional burners for pulverized fuel of this type, there are those shown in FIGS. 3 and 4.

In this embodiment, combustion air 10 sent from a ventilation device (not shown) is inside the burner, and
The air is divided into secondary air 11 and tertiary air 12.

The secondary air 11 forms a swirling flow by the secondary air swirling vane 8 provided at the inlet of the secondary air passage 2, and passes through the secondary air passage 2 to form an annular flow around the outer periphery of the mixture jet port 4. Secondary air outlet 5 provided in
The fuel is injected into the furnace 18 from the inside.

The tertiary air 12 forms a swirling flow by the tertiary air swirling vane 9 provided at the inlet of the tertiary air passage 3, and passes through the tertiary air passage 3 to the outer periphery of the secondary air outlet 5. The tertiary air is injected into the furnace interior 18 from a tertiary air jet port 6 provided in an annular shape in the section.

On the other hand, pulverized fuel is produced by using air or other gas as a conveying fluid from a pulverizer (not shown).
The pulverized fuel is fed into the mixture passage 1 in the burner through the pulverized fuel supply pipe 13 in the state of 5, and is injected from the mixture jet port 4 into the furnace 18 while forming a swirling flow by the mixture swirl vanes, where it is subjected to combustion. It is becoming more and more like this.

This air-fuel mixture passage 1 is provided with an auxiliary combustion burner 14 at its center. The auxiliary combustion burner 14
is used to ensure the ignition of the mixture 15 flame in cases where it is difficult to burn the mixture 15 alone, but liquid fuel or gas fuel 16, which is easy to burn, is used as the fuel. It's becoming like that.
Note that 17 is a burner throat.

In the conventional pulverized fuel burner shown in these two embodiments, since air jet ports are provided in one or more layers on the outer periphery of the mixture jet port 06 or 4, the injected mixture 018 or 15 is a relatively low temperature (generally 300
℃) air flow prevents contact with the hot combustion gases in the furnace 021 or 18. In order to form a stable flame, it is necessary that the ignition point of the flame be within the burner throat 020 or 17,
It is estimated that contact between the air-fuel mixture 018 or 15 and the high-temperature combustion gas is inhibited most strongly within the burner throat 020 or 17. Generally, the ignition temperature of pulverized fuel is approximately 500℃ or higher, and burner throat 02
In order to achieve ignition in the furnace 021 or 17, contact between the high temperature combustion gas in the furnace 021 or 18 and the mixture 018 or 15 is an essential condition.

Therefore, the conventional burner for pulverized fuel has the drawback that the ignition point of the flame is outside the burner throat 020 or 17, which causes the ignition point to fluctuate and the flame to become unstable.

The present invention was devised to solve these problems in the conventional technology, and involves sucking high-temperature combustion gas in the furnace into the burner throat and igniting the pulverized fuel within the burner throat. The object of the present invention is to provide a new burner for pulverized fuel that can form a stable flame.

In order to achieve this purpose, the pulverized fuel burner of the present invention has one or more layers of combustion air (some of the combustion exhaust gas mixed in In pulverized fuel burners that are equipped with jets (in some cases), a part of the annular airflow such as the air is cut off at these combustion air jets and the high-temperature combustion gas of the furnace is discharged from there. A shielding plate is provided to flow into the burner throat, and an operating stick is connected to operate the shielding plate to block part (multiple locations) of the combustion air flow that envelops the air-fuel mixture, and from there. The present invention is characterized in that the high-temperature combustion gas in the furnace is caused to flow into the burner throat and brought into contact with the air-fuel mixture to ignite a flame within the burner throat.

Hereinafter, the present invention will be described in detail with reference to illustrative embodiments. Note that the same reference numerals are used for the same components as those of the conventional pulverized fuel burner.

5 and 6 show a first embodiment, which is an improvement of the conventional pulverized fuel burner shown in FIGS. 1 and 2. FIG.

In FIG. 5, 118 is a mixture of pulverized fuel and air or other gas, and this mixture 1
There are 18 secondary combustion ports around the outside of the 106 jets.
Tertiary air nozzles 107 and 108 are provided, and a combustion primary air nozzle 105 is provided inside the nozzle 106, and an auxiliary combustion burner 117 is provided at the center thereof. 101 is a primary air passage communicating with the jet nozzle 105, 102 is a mixture passage communicating with the jet nozzle 106, 103 is a secondary air passage communicating with the jet nozzle 107, and 104 is the jet nozzle 10.
8, 109 is a primary air swirl vane provided in the air passage 101, 110 is a secondary air swirl vane, 111 is a tertiary air swirl vane, 112 is combustion air, and 113 is a primary air swirl vane. air, 1
14 is secondary air, 115 is tertiary air, 116 is a pulverized fuel supply pipe, 119 is liquid fuel or gas fuel, 120 is a burner slot, and 121 is inside the furnace.

That is, the symbols 101 to 121 in this embodiment correspond to the symbols 01 to 021 in the conventional embodiment shown in FIGS. 1 and 2, and have substantially the same configuration.

This embodiment differs from the conventional embodiments in that a secondary air outlet 107 and a tertiary air outlet 10 are provided around the outer circumference of the air-fuel mixture 118 outlet 106.
8 is provided with a movable air shielding plate 123 whose air shielding area can be adjusted from outside the burner.
A portion (multiple locations) of the flow of secondary air 114 and tertiary air 115 enveloping the air is cut off, and high temperature combustion gas 122 in the furnace 121 is allowed to flow in from there, and brought into contact with the air-fuel mixture 118 to create a flame. The ignition is performed within the burner throat 120.

The air shielding plate 123 has a structure in which the air shielding area is large in the case of pulverized fuel that is difficult to ignite, and is narrowed in the case of easy ignition, so that the amount of inflow of the high-temperature combustion gas 122 can be adjusted. This operation can be performed from outside the burner using an operating stick 124.

Therefore, the air shielding plate 12 is controlled by the operation stick 124.
When increasing the air shielding area of No. 3, a wide negative pressure area is created in the downstream part of the burner throat 120 near the air shielding plate 123, and there
High-temperature combustion gas 122 flows from 21 along the wall surface of the burner throat, and the gas flow hits the air shielding plate 123 and turns toward the center, making good contact with the air-fuel mixture 118 injected from the jet port 106. . Therefore, when the air-fuel mixture 118 is composed of a mixture of pulverized fuel that is difficult to ignite, it is effective to adjust the air shielding plate 123 to increase the air shielding area as described above.

Conversely, the air shielding plate 123 is controlled by the operation stick 124.
When reducing the air shielding area of the burner throat 1 downstream near the air shielding plate 123,
A narrow negative pressure area is generated in the area 20, and the amount of high-temperature combustion gas flowing there from the inside of the furnace 121 is small, and the mixture 1 injected from the jet port 106 is
The rate of contact with 18-year-olds is also low. Therefore, the mixture 11
When 8 is a pulverized fuel that is easy to ignite, it is sufficient to adjust the air shielding plate 123 to reduce the air shielding area as described above.

Figures 7 and 8 show the second embodiment, and Figures 3 and 4 show the second embodiment.
This is an improvement on the conventional pulverized fuel burner shown in the figure.

In FIG. 7, 15 is a mixture of pulverized fuel and air or other gas, and this mixture 15
Secondary and tertiary air jet ports 5 and 6 for combustion are provided doubly around the outer circumference of the jet port 4, and an auxiliary combustion burner 14 is provided at the center of the interior of the jet port 4.
Reference numeral 1 denotes an air mixture passage communicating with the jet nozzle 4, 2 a secondary air passage communicating with the jet nozzle 5, 3 a tertiary air passage communicating with the jet nozzle 6, and 7 inside the mixture passage 1. 8 is a secondary air swirling vane provided in the air passage 2; 9 is a tertiary air swirling vane 10 is provided in the air passage 3; 11 is a secondary air swirling vane; 12 is a secondary air swirling vane; 11 is a secondary air swirling vane; Tertiary air, 13 is a pulverized fuel supply pipe, 16 is liquid fuel or gas fuel, 17 is a burner throat, and 18 is inside the furnace.

That is, the symbols 1 to 18 in this embodiment are as shown in FIG.
The same components as those of the conventional embodiment shown in FIG. 4 are shown.

This embodiment is different from the conventional embodiments in that an air shielding plate 21 with a variable air shielding area is provided at the annular secondary and tertiary air jet ports 5 and 6 through which the combustion air 10 passes. , An operating rod 20 for adjusting the air shielding area is connected to the air shielding plate 21. Note that the broken arrow line in the figure indicates combustion gas 2.
2 shows the flow.

The operation of this second embodiment is also substantially the same as that of the first embodiment described above.

As described above, the pulverized fuel burner of the present invention has a mixture jetting port for injecting a mixture formed by mixing pulverized fuel and air or other gas into the furnace, and an outside of the mixture jetting port. In a pulverized fuel burner consisting of an annular nozzle that injects air or a mixture of air and other gas from the surroundings, a shielding plate whose area for shielding the air, etc. can be varied is provided at the annular nozzle. At the same time, since the operation stick for adjusting the shielding area is connected to the shielding plate, the high-temperature combustion gas in the furnace is sucked into the burner throat and the pulverized fuel is ignited in the burner throat. A stable flame can be formed.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of a first embodiment of a conventional burner for pulverized fuel, Fig. 2 is a view taken from Fig. 1 in the direction of the arrows, and Fig. 3
The figure is a vertical cross-sectional view of a second embodiment of a conventional burner for pulverized fuel, FIG. 4 is a view taken from the direction of the arrows in FIG. 3, and FIG. 6 is a side view of FIG. 5, and FIG. 7 is a vertical sectional view of the second embodiment of the pulverized fuel burner of the present invention.
FIG. 8 is a view taken from FIG. 7 in the direction of the arrows. 118,15...Mixture mixture, 106,4...Mixture outlet, 107,108,5,6...Blowout port,
123, 21... Shielding plate, 124, 20... Operation stick.

Claims (1)

[Scope of utility model registration request] A mixture jetting port that injects a mixture formed by mixing pulverized fuel and air or other gas into the furnace, and air or a mixture of air and other gas being injected from the outer periphery of the mixture jetting port. In a burner for pulverized fuel consisting of an annular jet nozzle, a shielding plate blocks a part of the annular airflow such as air from the annular jet nozzle and allows high temperature combustion gas in the furnace to flow from there into the burner throat. In addition to arranging
A burner for pulverized fuel, characterized in that an operating rod for operating the shielding plate is connected.